Turtle genomic novelty is driven by the evolution of ecological robustness

Area of Science:

• Evolutionary biology
• Comparative genomics
• Herpetology

Background:

• Turtles display significant diversity in morphology, ecology, and life history.
• Robust physiology is considered a key driver of turtle evolution, increasingly explored through comparative genomics.

Purpose of the Study:

• To investigate the genomic forces shaping turtle evolution using a large-scale genomic dataset.
• To apply a novel comparative method that flexibly analyzes correlations across species and genes.

Main Methods:

• Utilized a genomic-scale dataset encompassing diverse turtle species.
• Employed a novel comparative method based on Mahalanobis distances from gene-wise pairwise genetic matrices.
• Relaxed the assumption of a fixed species phylogeny in the analysis.

Main Results:

• Identified accelerated genes in closely related turtle groups, particularly Cryptodira and Emydidae.
• Functional enrichment analysis linked these accelerated genes to stress tolerance and immunity.
• Outlier analysis revealed shared evolutionary patterns among related species.

Conclusions:

• Ecological robustness, particularly stress tolerance and immunity, is a core adaptation in turtle evolution.
• Neutral evolutionary processes may also contribute to accelerated gene evolution in turtles.
• The findings highlight the importance of physiological adaptations in driving turtle diversification.